<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			//var num = 1.4;
			var num = -0.6;
			
			
			console.log(Math.abs(num));
			console.log(Math.floor(num));
			console.log(Math.ceil(num));
			console.log(Math.round(num));
			//正数四舍五入,负数五舍六入
			console.log(Math.random());
		</script>
	</body>
</html>
